Asymmetric Flaps
 

Hello;

Did anyone of you have experienced assymetric flaps (airbus, Boeing or Embraer) during a landing situation and what was the outcome?

Thanks.

Yes, I did and we survived.

Had it on a Meteor Mk 7.

Me, too (744). Run the checklist, land.

Flaps "fixed" themselves before we touched down.

"Anyone of you experienced asymmetric flaps?"*

Yes, I've met her......:ooh:!

OK, OK - IGMC!























*corrected for spelling and grammar.

Yes I have experienced this in a 737-800.
Selected flaps which didn't run.
Ran the trailing edge dissagree checlist(now deleted)
and attepted to extend the flaps with the alt flap
extension (electrric).
At this stage we go asymetric flap.(Great)
Ran the checklist for this and
this leads you to the trailing edge flap up landing check list.
Following investigation found that this had occured some
3-4 times in our fleet.
Bad batch of flap position sensors in the wheel well,
The supplier apprently used the wrong grease!
This took 40 minutes to compleat all checklists
and configure for landing. We burnt 2000kg of
fuel, Lukily I arrive with 4000kg overhead.
Not much fun after a 2 second sector, after a red eye!

On all modern jet aircraft, the flaps and slats have systems to stop assymetry. After one turn of flap drive on one side and not the other, the flaps stop and are locked. This is called flap assymetry nowadays.
The reason for this was brought home to me one day when we were clearing a B737-200 from a D check. All the flaps had been off and the flap tracks realigned etc so a flight test was invloved. After the first flight test the pilot reported that he could not get within 10kts of the stall speed as one wing was dropping. My very experienced supervisor told us to wind the flap torque tubes up half a turn on one wing and down half a turn on the other. The movement of the flaps is imperceptable.
The aircraft returned from its second test flight serviceable.
It made me respect the power of flaps on aircraft handling, and the reason for flap assymetry protection systems.

The company I work for recently include flap failures as part of our loft excercise. With a demonstration of
flight with assymetric flap!

We started with flap 1 on on side with 0 on the other
by the time the flaps got to 2 the aircraft(sim)
Was untrolable and would have ended in cotastorphy,
No doubt this is why the manufactures have
this protection bult in.

In addition I worked for a company that had EMB 145
One aircraft had a hyd failure. Should be no
major problem. But he crew used the speed brake to decend. The speed brake is held in using Hyd psi
so they had a floating speed brake on
approach, I think the check list was changed after
this occurance. ie not to use speed brak under this situation.

Yup, similar story into Murcia a couple of years ago in a 733 ...

When selecting Flaps 25, got assymetric indications. Went around - had a play - decided Flaps 15 would be the most appropriate thing to do and ran the QRH procedure.

Landed Flaps 15, and still made the normal exit without any extra braking ...

All in all - very uneventful

More of an issue in the simulator versus the aircraft.

In those glorious days when flying was dangerous, sex was safe, and both exciting, on the 707, flaps had to be selected asymetrically (outboard/inboard) to compensate for a jammed (or blocked, in case of runaway) stabilizer. But then there was a genius crew member on board called flight engineer, who would do it all.

Lemper, the flaps were NOT asymmetric, they were "split". So in that case, both inboard and both outboard flap panels moved in synch on each wing. Flap asymmetry is a different animal.

As a matter of fact, we used split spoilers too to overcome a jammed stab - remember the acronym "NUKI" - nose up - kill inboards and the flaps were opposite.

Had this on a B757 and there was nothing too it. Actioned the QRH and landed at flap 15. Just exercised the brakes a bit more than usual.

This is what used to happen with transverse push/pull rods and drum-stick links;

http://www.pprune.org/forums/showthr...=196858&page=2 Post 28, Viscount loss at Manch

http://www.pprune.org/forums/showthread.php?t=168959 Post 3 Ambassador loss at LHR.

Both were asymmetric, uncommanded flap retraction. An AVRO Tudor may have done something similar in 1951 but I don't want to get barred from the Forum.

Can't find it right away but will look more. There was a 737 (i think, maybe 727) where two flap drives failed at once and the asymmetric flap protection system, which only detected differences in flap position on the same side, did not detect anything wrong. Crew figured out the problem before it got out of hand, retracted flaps to where the airplane flew level, and landed.

Split and asymm, close to MLW, no checklist or other (handy) ref material to recommend a speed for this type of flap malfunction. Flap protections did their job.

The Boeing FCTM sates this particular malfunction cant happen.... but in the unlikley event, use Vref 30+70 for "flap up landing" with not too much AOB (memory fading a bit here & stand to be corrected ).

No flare required, stopped easily using less than max auto-brakes in CAVOK conditions. exceeded max tyre speeds.(dumping fuel would not have changed this)

Split Flaps ...
 

733 - Selected Flap 25 - left stayed at 15 and right went to 25 - long story short - it stayed that way - landed with very little noticeable difference - just a little bit more a'leron.

Why the question ?

Yep Mustaf....you're right indeed. Asymetric for split!!! I dunno where I put my head for this one; must have been stoned while typing!

A friend had assymetric flaps on a Lockheed 10 in the early 50's - He recognized the problem before he ran out of aileron, and retracted them. Landed no-flap (not too big a deal with that plane).

Broken torque tube was the culprit.

Had about 5 times on the 734 over the last 7 years ranging from between 1 and 5 to 25 and 30.

The immediate recycle of the flap level always bear no results. Best to discontinue approach,proceed to a hold,have a sip of water for a few minutes then most probably the larger flap will move back to the position commanded by the level which is a smaller settings once the system unfreeze its sensors and components.In case of hardware failure,do the checklist and land a little faster than usual with no drama,unless flap less than 5 with bald tyres could be more interesting.